fBm Noise

generator.fbm · Generators

Fractional Brownian motion of Perlin noise.

Purpose

The workhorse noise generator: layered Perlin noise that reads as natural, rolling ground. Reach for it as the base for hills and undulating terrain, or as detail to add onto a larger shape.

Wavelength is a real size. A 500 m feature stays 500 m when the world extent changes, so growing the world gives you more ground at the same scale rather than the same terrain stretched over it. Octaves then add detail below that size, each one finer than the last by the lacunarity.

Inputs

This node takes no inputs.

Outputs

• out

Parameters

Parameter	Type	Range	Default	Unit	Description	Field-driven
Wavelength (wavelength)	float	[0, 100000]	512	m	The distance from one crest to the next, in world units. On a noise generator it is the size of the largest features.	no
Octaves (octaves)	int	[1, 12]	5		The number of noise layers summed together; more octaves add finer detail.	no
Lacunarity (lacunarity)	float	[1, 4]	2		How much finer each octave is than the one before it; higher values widen the gap between coarse and fine detail.	no
Gain (gain)	float	[0, 1]	0.5		How much each finer octave contributes; higher values make the fine detail rougher and more pronounced.	no
Amplitude (amplitude)	float	[0, 100000]	256	m		no
Bias (bias)	float	[-100000, 100000]	0	m		no
Seed (seed)	int	[0, 2147483647]	0		The random seed; changing it regenerates a different variation of the same pattern.	no
Offset X (offset_x)	float	[-100000, 100000]	0	m	Slides the sampling window along the X axis, in world units, to take a different patch of the pattern without changing its shape.	no
Offset Y (offset_y)	float	[-100000, 100000]	0	m	Slides the sampling window along the Y axis, in world units, to take a different patch of the pattern without changing its shape.	no

Layer contract

Reads and writes the height layer.